1. Field of the Invention
The present invention relates to liquid sampling devices, and in particular, to a liquid samping apparatus which may be used to obtain samples of contaminants appearing on the surface of well water and directly beneath the surface thereof.
2. Discussion of the Relevant Art
The art abounds with devices which are used to sample liquids to determine the density, amount of contamination, etc. Generally, these devices disclose a valve which is sealed by the weight of the liquid sample contained in the container. Typical of the sampling devices which utilize a ball valve is U.S. Pat. No. 1,511,591 issued to Colligan on Oct. 14, 1924. The device disclosed therein is a liquid samplng apparatus that includes a plurality of tubular sections with the immersible end thereof being provided with a restricted portion which is sealed by the use of a spherical weight that is held by a pin above the level of the liquid to be sampled and, upon removal of the pin, is permitted to seal the restricted opening upon withdrawal of the sampling device.
Another device which utilizes a ball-type valve is disclosed in U.S. Pat. No 4,050,315 issued to Markfelt on Sept. 27, 1977. The apparatus disclosed therein is suitable for taking liquid samples in a well at any desired level under the surface and includes a body having a bullet-nosed weighted lower end in order to help avoid disturbing the surface of the water in the well as it is applied thereto. The apparatus requires that the lowering cable be jerked when the sampling device reaches the level at which a sample is to be obtained. By utilizing a pair of ball valves the fluid is permitted to enter the sampling chamber wherein a second ball floats to the surface within the chamber closing the inlet port thereby preventing contamination at higher levels from entering the sample chamber.
Generally, these devices are complicated mechanisms and require one or more movements of a string or contact with the bottom surface of the container for operation. The use of these devices on the surface of liquids would appear to disturb the liquids from which a sample is to be obtained thereby providing erroneous results by not including the liquids that may be floating on the surface from which the sample is to be taken. Moreover, the relatively simple devices discussed above may easily be rendered ineffective by dirt, or other particles which may enter the opening of the valve preventing the proper seating of the valve closing mechanisms. In addition, utilizing the sampling apparatus over long periods of time can cause particle buildup which again can prevent the sampling apparatus from operating properly.